MIT Makes Washable LED Fabric

Let’s face it, one of the challenges of wearable electronics is that people are filthy. Anything you wear is going to get dirty. If it touches you, it is going to get sweat and oil and who knows what else? And on the other side it’s going to get spills and dirt and all sorts of things we don’t want to think about on it. For regular clothes, that’s not a problem, you just pop them in the washer, but you can’t say the same for wearable electronics. Now researchers at MIT have embedded diodes like LEDs and photodetectors, into a soft fabric that is washable.

Traditionally, fibers start as a larger preform that is drawn into the fiber while heated. The researchers added tiny diodes and very tiny copper wires to the preform. As the preform is drawn, the fiber’s polymer keeps the solid materials connected and in the center. The polymer protects the electronics from water and the team was able to successfully launder fabric made with these fibers ten times.

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Joe Grand is Hiding Data in Plain Sight: LEDs that Look Solid but Send a Message

Thursday night was a real treat. I got to see both Joe Grand and Kitty Yeung at the HDDG meetup, each speaking about their recent work.

Joe walked us through the OpticSpy, his newest hardware product that had its genesis in some of the earliest days of data leakage. Remember those lights on old modems that would blink when data is being transmitted or received? The easiest way to design this circuit is to tie the status LEDs directly to the RX and TX lines of a serial port, but it turns out that’s broadcasting your data out to anyone with a camera. You can’t see the light blinking so fast with your eyes of course, but with the right gear you most certainly could read out the ones and zeros. Joe built an homage to that time using a BPW21R photodiode.

Transmitting data over light is something that television manufacturers have been doing for decades, too. How do they work in a room full of light sources? They filter for the carrier signal (usually 38 kHz). But what if you’re interested in finding an arbitrary signal? Joe’s bag of tricks does it without the carrier and across a large spectrum. It feels a bit like magic, but even if you know how it works, his explanation of the hardware is worth a watch!

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Bumblebee Breakout, a DIY Wearable Connector

The practice of developing wearable electronics offers a lot of opportunity for new connector designs and techniques for embedding electronics. Questions like these will eventually come up: How will this PCB attach to that conductive fabric circuit reliably? What’s the best way to transition from wire to this woven conductive trim? What’s the best way to integrate this light element into this garment while still maintaining flexibility?

Mika Satomi and Hannah-Perner Wilson of Kobakant are innovators in this arena and inspire many with their prolific documentation while they ask themselves questions similar to these. Their work is always geared towards accessibility and the ability to recreate what they have designed. Their most recent documented connector is one they call the Bumblebee Breakout. It connects an SMD addressable RGB LED, such as Adafruit’s Neopixel, to a piece of side glow fiber optic 1.5mm in diameter. On a short piece of tubing, the four pads of the SMD LED are broken out into four copper rings giving it the look of a striped bumblebee. To keep from shorts occurring while wrapping the copper tape contacts around the tube, they use Kapton tape to isolate each layer as they go.

This connector was originally created to be used in a commission they did out of Koba, their e-textile tailor shop located in Berlin. Fiber optics were applied to jackets for a performance called “All Your Base Are Belong To Us” produced by the Puppetry Department of the Hochschule für Schauspielkunst Ernst Busch.

Peruse more e-textiles techniques and learn how to build a connector transitioning from an embroidered thread bus to a wire and how to knit solderable circuit boards. And make sure to click around Kobakant’s website, it’s full of e-textile DIY tutorials!